I have been recently having problems shutting down my MBP. When I hit shutdown, it just pulls up that ticking circle thing in the middle and will not shut off. This has happened recently after downloading the 10.5.3 update. I have also recently downloaded skype. I have deleted skype and it still will not shut down. I have also tried resetting the PRAM (command+option+p+r) during startup. Any thoughts? Thanks.